Luminescence Properties Study Of Near-infrared Quantum Cutting In RE/Yb³⁺(RE=Tm³⁺, Pr³⁺, Eu²⁺) Co-doped Phosphate Glasses

At present, it is very necessary for human to develop and use vigorously clean and renewableenergy due to the more and more wasting resource. The solar cells have become so important in theworld energy structure that they have been studied widely because of their unique structure andfunction, and many paper about how to improve the efficiency have been reported by now.However, the application of solar cells have not been used widespread in our daily life because ofall the solar cells have faults of the high cost and low photoelectric conversion efficiency.Based on the purpose of improving the conversion efficiency of solar cells, the paper wasreported to study the glasses materials’ luminescent properties and mechanism, and the near-infrared quantum cutting in RE/Yb³⁺(RE=Tm³⁺, Pr³⁺, Eu²⁺) co-doped phosphate glasses, whichmight be provide support to improving the efficiency. The phosphate glasses used in this paperwere prepared containing Tm³⁺/Yb³⁺, Pr³⁺/Yb³⁺and Eu²⁺/Yb³⁺by the melting-and-quenchingmethod, then the absorption spectra, the excitation and emission spectra, and the fluorescencedecay curves spectra were measured to analysis their luminescent properties and energy transfermechanism based on Judd-Ofelt and Inokuti-Hirayama theory. Meanwhile, the influence law ofluminescence by the concentration of Yb³⁺had also been discussed and studied in order to give thetheoretical basis on develop solar cells.In capturer one, we introduced the global energy crisis and the necessary of using vigorouslyclean energy, and the sort and operating principle of solar cells and their faults. It was also pointedthat the quantum cutting can improve effectively the conversion efficiency of solar cells. Thequantum cutting, by modifying solar spectrum, means that the phosphors absorb one photon andemit two near-infrared photons, with optical quantum efficiency close to200%.In capture two and three, The main theories of this article can be cited, including the theory ofthe phosphate glass fabrication, the theory of the luminescence of the rare earths, the theory of theenergy transfer between the rare earths, the Judd-Ofelt theory and the Inokuti-Hirayama theory.One of the biggest innovations in this paper is the discussion of energy transfer between the rareearths in quantum cutting by the Inokuti-Hirayama theory. Then the methods and principle and testequipment have also introduced.The capture of four, five and six were the core of this paper, in which we discussed detailedlythe luminescence properties of near-infrared quantum cutting in Tm³⁺/Yb³⁺, Pr³⁺/Yb³⁺andEu²⁺/Yb³⁺co-doped phosphate glasses. We have calculated the optimal concentration ratio, the decay lifetimes, the energy transfer efficiency and quantum efficiency by measured the absorptionspectra, excitation and emission spectra,the decay curves, analyzed the energy transfer process byschematic energy levels diagram. Finally, the theory of Inokuti-Hirayama can be used to fix thedecay curves and get the parameters of all emission decay in three system, and demonstrated theenergy transfer is depend on the electric dipole-dipole interactions between luminescent centers.In the last capture, we concluded and summarize the properties of the absorption, theluminescence and the law of emission decay of all studied quantum cutting systems, and comparedthe advantages and disadvantages between them, finally predicted the development on the study ofTm³⁺/Yb³⁺, Pr³⁺/Yb³⁺and Eu²⁺/Yb³⁺co-doped quantum cutting in the future.